kill off civilization or send us into the dark ages but maybe only destroyed new york city. and of those asteroids, we know well less than 1% of those. so right now the metaphor in time that we're likely to get from one of those is zero. >> and let me ask a final question. what is our capacity if we discovered a sizable what that was on a collision course? what is our capacity right now to do something to change that? >> if you find it early, decades in advance, which is what the goal of mass is to do, and the goal is to be -- we have many options. then you only need to change the trajectory by very, very tiny amount. senator nelson, you know from having flown in space that when you're many orbits ahead of time, very tiny changes in your speed make big differences in the timing of where you are many orbits later and that's exactly what you do. so in real terms, if you change an asteroids speed of something like one millimeter per second, that's about the speed that in and walks. and to do that 10 years or more, before squinting at the earth, you can make it miss the earth.